Abstract: OBJECTIVE To analyze the changes of PCT and IL-6 in patients with positive blood cultures. METHODS Clinical data of 184 cases of hospitalized patients with positive blood cultures from Jan.2015 to Jun.2016 were retrospectively analyzed. The differences of PCT and IL-6 in patients with bloodstream infection were compared, including gram-negative bacteria (104 cases), gram-positive bacteria (69 cases), and fungi (11 cases). RESULTS The levels of PCT and IL-6 observed in patients with gram-negative bacteria infection were higher than those with gram-positive bacteria infection. PCT and IL-6 of patients after infection of gram-negative bacteria, gram-positive bacteria and fungal bloodstreams were log-transformed into lgPCT and lgIL-6, and independent samples t-test was carried out. There was significant difference in lgPCT between gram-negative bacteria and gram-positive bacteria bloodstream infection(P<0.05). There were significant differences in lgPCT among different pathogens such as gram-negative bacteria, suspected contamination bacteria (Streptococcus viridans and coagulase-negative Staphylococci) and gram-positive bacteria (gram-positive bacteria other than S.viridans and coagulase-negative Staphylococci) (P<0.05). There were significant differences in lgIL-6 among gram-negative bacteria, fungi and suspected contamination bacteria (P<0.05), but no significant difference with gram-positive bacteria. The positive correlation of lgPCT and lgIL-6 was existed, with the coefficient r=0.422(P<0.01). CONCLUSION The combined examination of IL-6 and PCT can detect early infection,discriminate infection and contamination, which can provide the basis for clinical diagnosis and application of antibiotics.